The ultrasonic pulverization of an aerosol offers an attractive alternative for the deposition of sol-gel thin films. Accurate control of the deposition device temperature and of the solvent vapour partial pressure during aerosol transport and deposition allows the deposition of a very large range of tetraethylorthosilicate-water-HCl-ethano solutions. The influence of the solution composition and of the post-deposition treatment on density and purity of the annealed SiO2 films is discussed. The influence of ultrasonication on the chemical properties of the source solutions is also contemplated. Fourier transform IR spectroscopy, spectroscopic ellipsometry and viscosity measurements have been used for characterizations.